<template>
  <div id="app">
    <div class="container">
      <!-- 顶部框模块 -->
      <div class="form-group">
        <div class="input-group">
          <h4>品牌管理</h4>
        </div>
      </div>

      <!-- 数据表格 -->
      <table class="table table-bordered table-hover mt-2">
        <thead>
          <tr>
            <th>编号</th>
            <th>资产名称</th>
            <th>价格</th>
            <th>创建时间</th>
            <th>操作</th>
          </tr>
        </thead>
        <tbody>
          <tr v-for="obj in list" :key="obj.id">
            <td>{{obj.id}}</td>
            <td>{{obj.name}}</td>

            <!-- 如果价格超过100，就有red这个类 -->
            <td :class="{red:obj.price > 100}">{{obj.price}}</td>
            <!-- 使用创建的过滤器formData -->
            <td>{{obj.time | formData}}</td>
            <td><a href="#" @click = 'abtn(obj.id)'>删除</a></td>
          </tr>
          <tr style="background-color: #EEE">
            <td>统计:</td>
            <td colspan="2">总价钱为: {{ allPrice }}</td>
            <td colspan="2">平均价: {{ svgPrice }}</td>
            </tr>
        </tbody>
          
        <tfoot >
          <tr>
            <!-- this.list.length ===0  判断数组为空,为空显示,不为空隐藏 -->
            <td colspan="5" style="text-align: center" v-show="this.list.length ===0">暂无数据</td>
          </tr>
        </tfoot>
           
      </table>

      <!-- 添加资产 -->
      <form class="form-inline">
        <div class="form-group">
          <div class="input-group">
            <input
              type="text"
              class="form-control"
              placeholder="资产名称"
              v-model = 'name'
            />
          </div>
        </div>
        &nbsp;&nbsp;&nbsp;&nbsp;
        <div class="form-group">
          <div class="input-group">
            <input
              type="text"
              class="form-control"
              placeholder="价格"
              v-model.number = 'price'
            />
          </div>
        </div><br>
        &nbsp;&nbsp;&nbsp;&nbsp;
        <!-- 阻止表单提交 -->
        <button class="btn btn-primary" @click.prevent ='btn' >添加资产</button>
      </form>
    </div>
  </div>
</template>

<script>
// 下载引用moment第三方模块包
import moment from 'moment'
export default {
  data() {
    return {
      name: "", // 名称
      price: '', // 价格
      // isShow: false, //暂无数据,显示隐藏
      list: [
        { id: 100, name: "外套", price: 199, time: new Date('2010-08-12')},
        { id: 101, name: "裤子", price: 34, time: new Date('2013-09-01')},
        { id: 102, name: "鞋", price: 25.4, time: new Date('2018-11-22')},
        { id: 103, name: "头发", price: 19900, time: new Date('2020-12-12')},
      ],
    };
  },
methods: {
  btn(){
    // 判断为空 
    if(this.name.trim() ==='' || this.price === '') return alert('产品信息不能为空！')
    // 判断页面元素是否为空,为空重置
    let id = this.list.length > 0 ? this.list[this.list.length-1].id + 1 : 100 
     this.list.push({
       id:id,
       name:this.name,
       price:this.price,
       time:new Date(),
     })
     this.name = ''
     this.price = ''
  },
  abtn (id){
     this.list.map((item,index)=> item.id === id ? this.list.splice(index,1) : item) 
  }
},
// 创建过滤器,处理日期格式
filters:{
  formData (val){
     return moment(val).format('YYYY-MM-DD')
  }
},
computed:{
  allPrice (){
    return this.list.reduce((sum,obj)=> sum += obj.price,0)
  },
  svgPrice(){
    return this.list.length > 0 ? (this.allPrice/this.list.length).toFixed(2):0
  }
}
};
</script>

<style >
.red{
  color: red;
}
.input-group {
 justify-content: center;
}
</style>